Recording medium for storing start position information for each zone and method and apparatus of managing data using the information

ABSTRACT

A recording medium for storing start position information for each zone, a method of managing data using the information, and an apparatus for recording the information and controlling recording and reproduction of data based on the recorded information. In a disc having a plurality of zones which form a group, and a spare area which is allocated at the start portion or the end portion of the group for replacing defects, when start logical sector numbers of each zone are changed by slipping replacement during initialization or reinitialization, the information is stored in the defect management area to thereby increase the compatibility of the medium. In particular, by the method and apparatus of managing data using information stored in a defect management area, generation of errors is prevented in reading or writing due to the change of a physical position of a real-recorded file which are caused by wrong calculation of the start logical sector numbers for each zone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Application No. 98-61603,filed Dec. 30, 1998, in the Korean Patent Office, the disclosure ofwhich is incorporated herein by reference.

This application is a continuation of U.S. Ser. No. 10/681,180, filedOct. 9, 2003 now U.S. Pat. No. 7,401,250, currently pending, which is acontinuation of U.S. Ser. No. 09/639,094, filed Aug. 16, 2000 and whichissued as U.S. Pat. No. 6,658,588 on Dec. 2, 2003, which is acontinuation-in-part of U.S. Ser. No. 09/474,748, filed Dec. 29, 1999and which issued as U.S. Pat. No. 6,725,400 on Apr. 20, 2004, thedisclosures of which are incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of optical recording media,and more particularly, to a disc for storing information of startpositions for each zone after initialization or reinitialization of therecording medium, which has a spare area for defect management of agroup formed of a plurality of zones, to a method of managing data usingthe information, and to an apparatus for managing data by recording theinformation and using the information.

2. Description of the Related Art

A disc is divided into zones so that inexactness of recording due to achange in speed of a spindle and deterioration of a search speed, whichoccur in a constant linear velocity (CLV) method are suppressed, and azoned constant linear velocity (ZCLV) method is used to obtain a higherrecording density than that obtained by a constant angular velocity(CAV) method.

A recordable and/or rewritable disc managed by a predetermined method ofmanaging defects may have a defective area, which can be detectedthrough a certification process, when the disc is initialized. In orderto manage the defects, physical sector numbers for indicating physicalposition on the disc and logical sector numbers for recording andmanaging a file by a file system, are separately managed. Logical sectornumbers are sequentially given to record and reproduce a file by a filesystem, in areas other than areas which are for recording a file, suchas a lead-in area or a guard area for adjusting the change of speed at aboundary between zones, and an area where defects are generated. A fileis recorded on a disc and reproduced from the disc using logical sectornumbers according to the file system, and a recording and/or reproducingapparatus receives a logical sector number from the file system as aposition to be recorded and/or reproduced, and then searches for aphysical sector number corresponding to the logical sector number toperform recording and/or reproduction.

When a reproducing apparatus or a recording apparatus makes an error incalculation of the logical sector number, the file is recorded in aphysically wrong area, so that the file cannot be read by anotherreproducing apparatus. Also, the file overlaps with previous recordeddata, so that the previous recorded data is spoiled.

SUMMARY OF THE INVENTION

To solve the above problems, it is an object of the present invention toprovide a recording medium which is divided into a plurality of zones bya method of controlling the speed for each zone such as a zoned constantlinear velocity or a zoned constant angular velocity, and information onthe start position of each zone is stored after initialization orreinitialization of the recording medium which forms a group from aplurality of zones and has a spare area for defect management.

It is another object of the present invention to provide a method ofmanaging data on the basis of the start position information of eachzone recorded on the disc, to minimize damage of data due to errors incalculation of the start logical sector number generated by recordingand/or reproducing apparatuses which are different from each other andensure stable recording and/or reproducing of data.

It is another object of the present invention to provide an apparatusfor managing data by recording start position information of each zoneon the disc and on the basis of the start position information of eachzone recorded on the disc, to minimize damage of data due to errors incalculation of the start logical sector number generated by recordingand/or reproducing apparatuses which are different from each other andensure stable recording and/or reproducing of data.

Additional objects and advantages of the invention will be set forth inpart in the description which follows and, in part, will be obvious fromthe description, or may be learned by practice of the invention.

Accordingly, to achieve the first object of the present invention, thereis provided a recording medium comprised of a plurality of zones inorder to manage defects, wherein the plurality of zones form a group,and a spare area for replacing defects for the group is allocated, andstart position information for each zone is stored in a predeterminedarea.

To achieve the second object of the present invention, there is provideda method of managing data for a reproducing only apparatus in which aplurality of zones form a group to manage defects of the disc, a sparearea for replacing defects for the group is allocated, and startposition information for each zone is stored in a predetermined area,comprising the steps of: reading start position information, which isstored in the predetermined area, for each zone; and accessing data onthe basis of the read start position information and reproducing theaccessed data.

To further achieve the second object of the present invention, there isprovided a method of managing data for a recording and reproducingapparatus in which a plurality of zones forms a group to manage defectsof the disc, a spare area for replacing defects of the group isallocated, and the start position information for each zone is stored ina predetermined area, comprising the steps of: reading the startposition information for each zone, which is stored in the defectmanagement area; calculating the start position information for eachzone on the basis of primary defect list information; and performingreading and writing of data when the read start position information isidentical to the calculated start position information.

Also, the method further comprises the step of reading the data on thebasis of the start position information stored in the predetermined areawhen the read start position information is not identical to thecalculated start position information.

To achieve the third object of the present invention, there is providedan apparatus to determine and record the start position information in apredetermined area of the disc for reproducing and recording of data tothe disc, where the disc includes a plurality of zones forming a groupto manage defects of the disc, a spare area for replacing defects forthe group, and start position information for each zone is stored in apredetermined area. The apparatus for managing data includes a pickup toread the stored start position information for each zone and acontroller to calculate a second start position information for eachzone based upon a primary defect list information, wherein thecontroller controls reproduction and recording of data when the storedstart information is identical to the second start position information.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will becomemore apparent by describing in detail preferred embodiments thereof withreference to the attached drawings, in which:

FIGS. 1A and 1B show the relationship between a one-dimensionalstructure of a disc having a size of the DVD-RAM standard version 1.0and a start logical number of each zone;

FIGS. 2A and 2B show a change of a start logical sector number of eachzone caused by slipping replacement in the disc, which has a groupformed of a plurality of zones;

FIGS. 3A and 3B show a change of the starting position of data which isrecorded by the miscalculated logical sector number in the structure ofthe disc of FIGS. 2A and 2B;

FIGS. 4A and 4B show an example of the structure of a table whichincludes information on the start position for each zone in a defectmanagement area according to the present invention;

FIG. 5 is a flowchart of a data management method of a reproducing onlyapparatus according to an embodiment of the present invention;

FIG. 6 is a flowchart of a data management method of a recording andreproducing apparatus according to an embodiment of the presentinvention; and

FIG. 7 is a block diagram of a recording/reproducing apparatus forimplementing the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now made in detail to the present preferred embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings, wherein like reference numerals refer to the likeelements throughout. The embodiments are described below in order toexplain the present invention by referring to the figures.

In order to manage defects on a general recordable and/or rewritabledisc, slipping replacement, for skipping defects without providinglogical sector numbers to the defects, is used for defects (primarydefects) generated upon initialization of the disc, and linearreplacement for replacing error correction code (ECC) blocks of anerroneous zone with normal blocks in a spare area, is used for defects(secondary defects) generated during use of the disc.

That is, slipping replacement is used to minimize a reduction in therecording or reproduction speed due to defects, in which a logicalsector number is provided to a sector which is determined to bedefective during a certification process for inspecting defects of adisc when the disc is initialized. Here, the logical sector number isprovided to a sector next to the defective sector, that is, data isrecorded or reproduced by skipping a sector where a defect is generatedduring recording or reproduction. Here, an actual physical sector numberis shifted by the sector number designated by skipping the defectivesector. Such a shifting-backwards phenomenon is solved by using the samenumber of sectors in a spare area located at the end portion of arecording area (a group or a zone) as the number of defects in therecording area. According to the specifications, the position of adefective sector replaced by slipping replacement is prescribed to berecorded in a primary defect list (PDL) in a defect management area(DMA) on a disc.

Slipping replacement cannot be used for a defect which is generatedwhile a disc is being used. When a defective portion is disregarded orskipped, discontinuity is introduced into the logical sector numbering,which means that slipping replacement violates file system rules. Thus,linear replacement is used for defects generated during use of the disc,in which an ECC block including a defective sector is replaced by an ECCblock existing in a spare area. The location of the defective ECC blockreplaced by linear replacement is prescribed to be recorded in asecondary defect list (SDL) in defect management area on a disc. Whenlinear replacement is used, logical sector numbering is not interrupted.However, when there is a defect, the positions of sectors on a disc arediscontinuous, and real data for a defective ECC block exists in a sparearea.

Meanwhile, a digital versatile disc random access memory (DVD-RAM)according to the DVD-RAM standard version 1.0 includes a plurality ofgroups each having a user area and a spare area. That is, FIGS. 1A and1B one-dimensionally show a logical area and a physical area on part ofa disc, respectively, where each zone of the physical area includes aguard area, a user area, a spare area, and a guard area which aresequentially arranged. In FIG. 1A, the letters m, m+1, n, n+1, p, andp+1 represent the end logical sector number of a first zone, the startlogical sector number of a second zone, the end logical sector number ofthe second zone, the start logical sector number of a zone immediatelybefore the last zone, and the first logical sector number of the lastzone, respectively, when there are no defects. That is, referencenumerals 101, 102, 103, 104 and 105 denote a user area, a spare area, aguard area, defective sectors and a spare area replaced by slippingreplacement, respectively. The guard area 103 is a buffering area forpreventing driving from becoming unstable due to the differences inrotation speed between zones, and is allocated at the start and the endpositions of each zone. The spare area 102 of FIG. 1B indicates a sparearea of a predetermined size allocated by a standard. The spare area 102is constant in each zone. Also, the spare area 105 indicates a portionof the spare area 102 which is already used by slipping replacement dueto defective sectors 104.

In a conventional method for managing defects, a group is formed of onezone, and a spare area is allocated at the end of each group. Each groupis managed as a defect management area. Also, FIG. 1B shows theshifting-backwards phenomenon in which a logical sector number isshifted backwards by slipping replacement. However, when spare areas arearranged in each zone, the shifting phenomenon of a logical sectornumber ends at the spare area of the corresponding zone and the startlogical sector number of the next zone is predetermined without beingaffected by the number of defects as shown in FIG. 1A. Thus, the startlogical sector numbers of each of the groups are predetermined by astandard so that when data on the disc is read, the start logical sectornumbers for each group may not be separately managed to search for thecorresponding group.

However, the start logical sector number of each group is designated asdescribed above. Thus, when defects in a group are managed by slippingreplacement, slipping replacement must be performed only within acorresponding group. In order to replace defects generated in acorresponding group using the slipping replacement, the number ofdefective sectors that are slipped must be less than the number ofusable sectors in a spare area of the corresponding group. Thus, arestriction that a large defect generated in a group must be processedwithin the same group limits the maximum size of a defect that can bereplaced by slipping replacement.

If the size of defects to be replaced by slipping replacement is greaterthan the size of a spare area in a corresponding group, a spare area inanother group must be used by linear replacement. However, when linearreplacement is used, defects are managed not in units of sectors but inunits of ECC blocks, that is, in units of 16 sectors. Thus, a spare areaof 16 sectors is required to process one defective sector, whichdegrades the efficiency of defect management. Also, a standard size of aspare area for defect management is predetermined, so that a spare areaof the predetermined size must also be allocated in applications towhich defect management using linear replacement cannot be applied, suchas real time recording. Therefore, the efficiency of area utilization ofa disc is degraded.

To solve these problems, there is proposed a method of managing defectsin which a group is formed of a plurality of zones and a spare area isallocated at the start portion of the group and/or the end thereof.

When a group is formed of a plurality of zones, the start logical sectornumber for each zone depends on the number of defects. Particularly,when a spare area exists at the position in which the group starts, theslipping replacement must be performed backwards, to thereby complicatecalculation in initialization. Particularly, slipping replacement causesmisalignment of the start sector of an ECC block at a start position ofa zone, so that a fragmented ECC block is located at the zone boundary.When sectors which cannot form an ECC block at a boundary between zonesare skipped to prevent the fragmented ECC blocks of each zone,calculation of the start logical sector number with respect to each zonebecomes more complicated.

That is, FIGS. 2A and 2B show a logical area and a physical area of adisc, respectively, in which a plurality of zones form a group, a sparearea for slipping replacement is allocated at the group, and the startlogical sector number of each zone is changed. Each zone includes aguard area, a user area, and a guard area, and a spare area 204 for agroup is allocated at the end portion of the group. Reference numerals201, 202 and 203 denote a user area, a guard area and defective sectors,respectively.

When a zone #0 (first zone) has no defects, the logical sector numberwhich is allocated as the start logical sector number of a zone #1 (thesecond zone) is m+1, and when there are no defects, the start logicalsector number of a third zone is n+1, and when a defect is generated ineach zone during initialization, the start logical sector number isshifted backwards by an amount equal to the number of the defectivesectors.

That is, as shown in FIG. 2B, when the number of defective sectors inthe zone #0 is i, the logical sector numbers are shifted backwards by i.If there are no defects, as shown in FIG. 2A, the final logical sectornumber allocated to the zone #0 is m, however, the final logical sectornumber allocated to the first zone according to the number i ofdefective sectors is m−i.

Thus, in the DVD-RAM standard version 1.0, when the size of a user areaallocated to the first zone is m sectors, the start logical sectornumber of the zone #1 starts from m+1, but when each zone has no sparearea, the start logical sector number of the next zone is shifted by ias shown in FIG. 2B so that the start logical sector number of the zone#1 is m−i+1.

In the next zone (zone #2), when the number of defects generated fromthe start of the group to the same zone (zone #2) is j, the startlogical sector number is shifted to n−j+1. At this time, i and j mayfurther include unused sectors for preventing the start position of theECC block from misaligning at each boundary between each zone due to adefective sector, i.e., for skipping the remaining sectors which cannotform an ECC block at the end of each zone. Thus, the start logicalsector number for each zone is shifted backwards by the additional sparearea.

Here, the spare area 204 may be allocated at the end portion of a groupor the start portion thereof. When the spare area 204 is allocated atthe start portion of group, reverse slipping replacement is performed,which complicates calculation of the start logical sector number foreach zone. In reverse slipping replacement, the slipping replacement isperformed in reverse and the remaining sectors which cannot form an ECCblock, which are generated at a boundary between zones after theslipping replacement, are reallocated at the final portion of the zone,which complicates calculation.

Also, when the file system is generally recorded at a portion where thelogical sector number of the disc starts, the spare area is positionedat the start portion of the group, and the calculation is wrong, thefile system cannot be read due to the forward shifting of the logicalsector number.

Thus, when defects are managed in the group forming a plurality ofzones, the start logical sector number for each zone is changed so thatthe recording and/or reproducing apparatus must calculate the startlogical sector number for each zone to perform normally recording and/orreproduction of data on/from a disc. Meanwhile, in order to read thedisc in a reproducing only apparatus such as DVD-ROM reproducingapparatus and/or a DVD player, the start logical sector numbers for eachzone of the disc must be read, so that the size of the firmware of thereproducing apparatus is increased.

FIGS. 3A and 3B show the case of change of the start logical sectornumber of a zone when a complicated start logical sector number iswrongly calculated in a predetermined portion due to errors in designinga recording and/or reproducing apparatus or a software bug of afirmware. When the calculation of the logical start positions of zonesis complicated, and thus calculation of the start logical sector ofzones is wrong in a predetermined portion due to errors of software of amicrocomputer which controls initialization of the reproducingapparatus, a normal position of the physical area shown in FIG. 3Bcorresponding to a position of the logical area of the file in a zone #Kshown in FIG. 3A, which is 301, may be 302.

As shown in FIG. 3B, a zone 303 where logical sector numbers overlap, azone 304 where the logical sector number is wrong, or a zone 305 wherethe logical sector number is not designated, may be generated. Inparticular, zones 303 and 305 can be easily found, but zone 304 cannotbe easily found by any corresponding reproducing apparatus. In the drivesystem having a wrong calculation, wrong positions may be recorded or anormally recorded portion cannot be read due to the wrong calculation ofthe start logical sector number.

When the file is abnormally recorded, and a wrong recorded disc isrecorded and/or reproduced wrongly in a normal recording and/orreproducing apparatus, or a normally recorded disc is managed in arecording and/or reproducing apparatus in which the start logical sectornumber is wrongly calculated, the file may be wrongly read and written.In particular, when the defect management area is allocated to the startposition of the group, slipping replacement is performed in reverse sothat the first position of the logical sector number may be wrong, wherethe file system cannot be read.

To solve the above problem, when the start logical sector numbers foreach zone are determined after slipping replacement on initialization orreinitialization, the start logical sector numbers for each zone arestored in a disc definition structure (DDS) area of the defectmanagement area. That is, as shown in FIG. 4A, the start logical sectornumbers for each zone are recorded in the DDS area using a recordingitem of 4 bytes. Here, RBP shows a relative byte position, and startlogical sector numbers for 35 zones from a reserved 256th byte positionof the DDS area can be allocated in unit of 4 bytes, as an example. FIG.4B denotes the structure of the DDS where the start logical sectornumbers of 4 bytes for each zone are stored, where the start logicalsector numbers are recorded in 24 bits and the remaining bits arereserved.

When a disc on which the start logical sector numbers for each zone arerecorded is read or written in another recording and/or reproducingapparatus, the following operations may be performed.

The reproducing only apparatus requires no calculation of the startlogical sector numbers. This is because the recording and/or reproducingapparatus records data on the basis of the wrong start logical sectornumber even though the start logical sector number recorded in the DDSarea is wrong, and thus the reproducing only apparatus must read data onthe basis of the stored start logical sector number. Thus, it is mostsecure to read data with reference to the start logical sector numberrecorded in the DDS area without complicated calculation and regardlessof wrong calculation of the start logical sector number recorded in theDDS area. Thus, the reproducing apparatus requires no algorithm forcalculating the complicated start logical sector number to therebysimplify the firmware.

That is, in the reproducing only apparatus, as shown in the flowchart ofFIG. 5, the start logical sector number for each zone stored in the DDSarea is read (S101), and data is accessed based on the read startlogical sector number to be produced (S102).

Meanwhile, when the disc is installed in a recording and reproducingapparatus, the start logical sector number of the DDS area is read, butthe start logical sector number is calculated on the basis of PDLinformation of the defect management area. If the recorded informationis consistent with the information obtained by calculation, theapparatus performs normal recording and reproduction, and if not, theapparatus only reads data on the basis of the start logical sectorinformation recorded on the disc. This is because the data of the discis recorded on the basis of the start logical sector number which isstored in the DDS area for each zone. Also, it is most secure not torecord additional data until it is determined which information iswrong. Thus, information must not be recorded on the disc until it isdetermined why the start logical sector number of the disc isinconsistent and a proper action is performed.

That is, in the recording and reproducing apparatus, as shown in theflowchart of FIG. 6, the start logical sector number for each zonestored in the DDS area is read (S201), and the start logical sectornumber for each zone is calculated on the basis of the PDL informationof the defect management area (S202). Then, it is determined whether thestart logical sector numbers read in step 201 are identical to the startlogical sector numbers calculated in step 202 (S203), and if so, normaldata read and write operations are performed (S204). If not, the factthat the disc has an error is indicated to a user (S205), data is readon the basis of the start logical sector number stored in the DDS area(S206), and no data is recorded on the disc until the error is clearedby a fixing tool (S207).

As described above, the start logical sector number corresponding to thestart position information for each zone is stored in the defectmanagement area so that the reproducing only apparatus requires noalgorithm to calculate the complicated start logical sector number.

Also, when the stored information is inconsistent with the correspondingcalculated start position information for each zone, damage of data dueto errors of calculation of the start logical sector number generated byrecording and reproducing apparatuses which are different from eachother, using the stored start position information for each zone, isminimized and stability of the recorded data is increased.

Further, FIG. 7 is a block diagram of a recording/reproducing apparatusfor implementing the present invention. The function of therecording/reproducing apparatus for recording/reproducing A/V(audio/video) data using the recordable and rewriteable recording mediasuch as the DVD-ROM and DVD-RAM is largely divided into both calculatingstart position information for each zone during slipping replacement andrecording the calculated start position information in a predeterminedarea of the disc, e.g., the disc definition structure (DDS), andrecording and reproducing data based upon whether the recorded startposition information was identical to a calculated second start positioninformation based on the primary defect list (PDL) of the recordingmedia.

During recording, an AV codec and/or a host interface 310compression-codes an externally applied AV signal according to apredetermined compression scheme and supplies size information for thecompressed data. A digital signal processor (DSP) 320 receives thecompressed A/V data supplied from the AV codec and/or the host interface310, adds additional data for error correction code (ECC) processingthereto, and performs modulation using a predetermined modulationscheme. A radio frequency amplifier (RF AMP) 330 converts the modulateddata from the DSP into a radio frequency (RF) signal. Then, a pickup 340records the RF signal supplied from the RF AMP 330 on a disk mounted ona turn table of the pickup 340. A servo unit 350 receives informationnecessary for servo control from a system controller 360 and stablyperforms a servo function for the mounted disk.

Thus, both start position information for each zone and user data foreach zone can be recorded. Upon recording of the start positioninformation, system controller 360 will calculate the start positioninformation for each zone and control the pickup 340 to record the same.Likewise, when recording user data to user data areas of the zones,system controller 360 will control the pickup 340 to record the same, ifthe start position information for that zone equals the calculated startposition of that zone.

During playback of information data stored on the disk, the pickup 340picks up the optical signal from the disk having the information datastored therein, and the information data is extracted from the opticalsignal. The RF AMP 330 converts the optical signal into an RF signal,and extracts the servo signal for performing a servo function, andmodulated data. The DSP 320 demodulates the modulated data supplied fromthe RF AMP 330 corresponding to the modulation scheme used duringmodulation, performs an ECC process to correct errors, and eliminatesadded data. The servo unit 350 receives information necessary for servocontrol from the RF AMP 330 and the system controller 360, and stablyperforms the servo function. The AV codec and/or the host interface 310decodes the compressed A/V data supplied from the DSP 320 to output anA/V signal. The system controller 360 controls the overall system forreproducing and recording the information data from and on the diskmounted on the turn table of the pickup 340.

Similarly to the above recording of start position information, thepickup 340 reads the start position information for each zone. If thereproducing apparatus is only used for playing back recordedinformation, then the system controller 360 may control reproduction ofuser data based solely on the recorded start position information.Whereas, if the reproducing apparatus is utilized for both recording andreproducing of user data, then the system controller 360 will determinewhether the recorded start position information is equal to a calculatedstart position information, and if so, allow both reproduction andrecording of user data. However, if the system controller 360 determinesthat the recorded position information and start position informationare not the same, the system controller may prevent further recording tothe recording medium. In that case, the system controller may notify theuser that the recorded position information and calculated positioninformation are different.

The system controller 360 and the DSP 320 handle processing of the dataduring recording and reproduction, including performing requiredslipping or linear reproduction, when appropriate, in connection withinitialization and subsequent recording, reproduction, andreinitialization of the disc.

Although a few preferred embodiments of the present invention have beenshown and described, it would be appreciated by those skilled in the artthat changes may be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. A recording and/or reproducing apparatus to record and/or reproducedata to and/or from zones of a recording medium, with the recordingmedium having a spare area for defect management for a group including aplurality of the zones with the spare area being at an end of the group,the apparatus comprising: a pickup unit to read an information area ofthe recording medium, the information area having start positioninformation for each of the zones of the group, the start positioninformation including, for each zone, a corresponding start logicalsector number; and a controller to perform defect management using thespare area to replace a defective area in the zones of the group tomanage defects at a group level, wherein, for each of the plurality ofzones, the start logical sector number recorded in the start positioninformation is different.
 2. A recording and/or reproducing apparatus torecord and/or reproduce data to and/or from zones of a recording medium,with the recording medium having a spare area for defect management fora group including a plurality of the zones with the spare area being atan end of the group, the apparatus comprising: a pickup unit to read aninformation area of the recording medium, the information area havingstart position information for each of the zones of the group, the startposition information including, for each zone, a corresponding startlogical sector number; and a controller to perform defect managementusing the spare area to replace a defective area in the zones of thegroup to manage defects at a group level, and accessing the data byaccessing first data recorded in a first one of the zones according to afirst one of the start logical sector numbers recorded in the read startposition information, and accessing second data from a second one of thezones other than the first one of the zones according to a second one ofthe start logical sector numbers recorded in the read start positioninformation.